1. Field of the Invention
The present invention relates to an apparatus and method for video editing, and more particularly, to a video editing apparatus which is capable of editing data constituted by multiplexing image and sound data at a high rate.
2. Description of the Related Art
One example of a conventional video editing apparatus is described in JP-A-H11-155128. The conventional video editing apparatus described in this publication will hereinafter be described with reference to the drawings. As shown in FIG. 6, this conventional video editing apparatus is constituted of a DVD-RAM drive 1 and a host system 2. The DVD-RAM drive 1 roughly includes a main control unit (CPU) 10, an input/output interface 11, a data management table 12, an access control unit 13, a disk (DVD) 14, and an encoder/decoder 15.
An outline of an operation of the conventional video editing apparatus constituted as described above will hereinafter be described. That is, the CPU 10 of the DVD-RAM drive 1 records (telerecords) digital image information transferred from the host system 2 via the input/output interface 11 in the disk 14. Next, in response to a command from the host system 2 accompanying a user's input operation, the CPU 10 reads the recorded image information from the disk 14, and transfers the information to the host system 2 via the input/output interface 11.
Here, it is assumed that a user checks a screen to indicate a cut position for cutting image data in a first half of the image information. The CPU 10 specifies a group of pictures (GOP) corresponding to the indicated cut position, and the cut position in the GOP based on management information of the data management table 12.
The CPU 10 uses the specified cut position of a GOP as a reference position to detect a picture type of a top part of the image data part of a last half. In this case, the CPU 10 refers, for example, to a GOP header to recognize the picture type of the top part. Here, when the picture type of the top part is an I type, the CPU 10 converts the image data part of the first half in which the cut position is the reference position to a reproduction nullified data. This reproduction nullified data means user data which is incapable of being reproduced as the image information. On the other hand, when the picture type of the top part is not the I (intra picture) type, the CPU 10 controls the encoder/decoder 15 to execute a process of converting the picture type of the top part to the I type.
The CPU 10 executes a process of expanding a region of the image data part of the last half to a region of the first half by an increase obtained by the conversion to the picture data of the I type. Moreover, the CPU 10 converts the image data part of the first half to reproduction nullified data to produce a new GOP.
After executing the conversion process in the GOP, the CPU 10 sets a management table A for managing the image information including the newly produced GOP, and a management table B for managing the image information which is a cut object. In the data management table 12, the image information managed by the management table A is managed as continuous reproduction data. On the other hand, the image information which is the cut object is managed as irreproducible data.
However, the above-described conventional video editing apparatus has the following problems.
A first problem is that data in which image and sound data are multiplexed cannot be edited. A reason for this is that means for nullifying the sound data is not disposed.
A second problem is that correct reproduction of the edited data can be guaranteed only on a decoder having a function of interpreting the management table. This is because time information for synchronously reproducing the image and sound is not correct after the editing.
A third problem is that the nullified data region remains on the disk after the editing and a disk capacity is wasted. This is because means for deleting the nullified data region after the editing is not disposed.
A fourth problem is that an editing point needs to be manually designated by the user. This is because means for automatically providing candidates for the editing point to the user is not disposed.